Muscle tissue is divided into three primary types - skeletal, cardiac, and smooth muscle. Skeletal muscle is organized into motor units controlled by the nervous system and allows for voluntary movement. Contraction occurs when calcium ions are released, causing the thin and thick myofilaments to interact via cross-bridges, sliding the filaments and shortening the sarcomere. The amount of tension produced depends on factors like sarcomere length, stimulation frequency, and number of motor units recruited. Energy for muscle contraction is obtained primarily through aerobic metabolism of fats and carbohydrates.
This PPT cover the concepts of Pathophysiology of Renal failure. It includes different types of renal failure ie. Acute renal Failure and Chronic renal Failure
elimination, bowel elimination, physiology of elimination, process of bowel eliminaton factor impaired bowel, factors improve bowel elimination, alteration in bowel elimination, maintenance of bowel motility, assessment of bowel elimination, characteristics of feces, type of feces, methods for maintain the bowel elimination:- enemas, rectal suppositories and colostomies, types of colostomies, colostomy care
Frustrated with constant pain & medications for your kidney stone? Then supplement your medical treatment with dietary support. Following a correct diet plan for kidney stone will help you in controlling reoccurrence of it.
This PPT cover the concepts of Pathophysiology of Renal failure. It includes different types of renal failure ie. Acute renal Failure and Chronic renal Failure
elimination, bowel elimination, physiology of elimination, process of bowel eliminaton factor impaired bowel, factors improve bowel elimination, alteration in bowel elimination, maintenance of bowel motility, assessment of bowel elimination, characteristics of feces, type of feces, methods for maintain the bowel elimination:- enemas, rectal suppositories and colostomies, types of colostomies, colostomy care
Frustrated with constant pain & medications for your kidney stone? Then supplement your medical treatment with dietary support. Following a correct diet plan for kidney stone will help you in controlling reoccurrence of it.
Functions of Muscle Tissue
• Producing body movements
• Stabilizing body positions
• Regulating organ volumes
– bands of smooth muscle called sphincters
• Movement of substances within the body
– blood, lymph, urine, air, food and fluids, sperm
• Producing heat
– involuntary contractions of skeletal muscle (shivering
Molecular basis of Skeletal Muscle ContractionArulSood2
The ppt aims to explain the molecular basis of skeletal muscle contraction and certain applied aspects of the same. Sources include Guyton and Hall's Textbook of Physiology (South-Asia edition, Vol. 2) and C.L. Ghai's Textbook for Practical Physiology.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
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Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
1. Muscle Tissue
• One of 4 primary tissue types, divided
into:
– skeletal muscle
– cardiac muscle
– smooth muscle
Without these muscles, nothing in the body
would move and no body movement would
occur
2. Skeletal Muscles-
Organs of skeletal muscle tissue
- are attached to the skeletal
system and allow us to move
• Muscular System- Includes only skeletal
muscles
Skeletal Muscle Structures
• Muscle tissue (muscle cells or fibers)
• Connective tissues
• Nerves
• Blood vessels
3. 6 Functions of Skeletal Muscles
1. Produce skeletal movement
2. Maintain body position and posture
3. Support soft tissues
4. Guard body openings (entrance/exit)
5. Maintain body temperature
6. Store Nutrient reserves
4. How is muscle tissue organized at
the tissue level?
Organization of Connective Tissues
Figure 10–1
5. Organization of Connective Tissues
•
•
•
•
Muscles have 3 layers of connective
tissues:
1. Epimysium-Exterior collagen layer
Connected to deep fascia
Separates muscle from surrounding tissue
2. perimysium- Surrounds muscle fiber bundles
(fascicles)
Contains blood vessel and nerve supply to
fascicles
3. endomysium
7. Muscle Attachments
• Endomysium, perimysium, and
epimysium come together:
– at ends of muscles
– to form connective tissue attachment to
bone matrix
– i.e., tendon (bundle) or aponeurosis
(sheet)
8. Nerves
Skeletal muscles are voluntary
muscles, controlled by nerves of the
central nervous system
Blood Vessels
• Muscles have extensive vascular systems that:
– supply large amounts of oxygen
– supply nutrients
– carry away wastes
9. What are the characteristics
of skeletal muscle fibers?
• Skeletal muscle cells are called fibers
Figure 10–2
10. Skeletal Muscle Fibers
• Are very long
• Develop through fusion of mesodermal cells
(myoblasts- embryonic cells))
• Become very large
• Contain hundreds of nuclei –multinucleate
• Unfused cells are satellite cells- assist in
repair after injury
12. The Sarcolemma
• The cell membrane of a muscle cell
• Surrounds the sarcoplasm (cytoplasm
of muscle fiber)
• A change in transmembrane potential
begins contractions
• All regions of the cell must contract
simultaneously
13. Transverse Tubules (T tubules)
• Transmit action potential – impulses
through cell
• Allow entire muscle fiber to contract
simultaneously
• Have same properties as sarcolemma
• Filled with extracellular fluid
14. Myofibrils- 1-2um in diameter
• Lengthwise subdivisions within muscle fiber
• Made up of bundles of protein filaments
(myofilaments)
• Myofilaments - are responsible for muscle
contraction
2 Types of Myofilaments
• Thin filaments:
– made of the protein actin
• Thick filaments:
– made of the protein myosin
15. Sarcoplasmic Reticulum (SR)
• A membranous structure surrounding
each myofibril
• Helps transmit action potential to
myofibril
• Similar in structure to smooth
endoplasmic reticulum
• Forms chambers (terminal cisternae)
attached to T tubules
16. A Triad
• Is formed by 1 T tubule and 2 terminal
cisterna
Cisternae
• Concentrate Ca2+
(via ion pumps)
• Release Ca2+
into sarcomeres to begin
muscle contraction
17. Structural components of the
Sarcomeres
Figure 10–4
-The contractile
units of muscle
-Structural units
of myofibrils
-Form visible
patterns within
myofibrils
18. Muscle Striations
• A striped or striated pattern within
myofibrils:
– alternating dark, thick filaments (A bands)
and light, thin filaments (I bands)
19. M Lines and Z Lines
• M line:
– the center of the A band
– at midline of sarcomere
• Z lines:
– the centers of the I bands
– at 2 ends of sarcomere
Zone of Overlap
• The densest, darkest area on a light
micrograph
• Where thick and thin filaments overlap
20. The H Zone
• The area around the M line
• Has thick filaments but no thin
filaments
Titin
• Are strands of protein
• Reach from tips of thick filaments to
the Z line
• Stabilize the filaments
22. Sarcomere Function
• Transverse tubules encircle the
sarcomere near zones of overlap
• Ca2+ released by SR causes thin and
thick filaments to interact
28. 4 Thin Filament Proteins
–
–
–
–
–
–
–
1. F actin:
is 2 twisted rows of globular G actin
the active sites on G actin strands bind to myosin
2. Nebulin:
holds F actin strands together
3. Tropomyosin:
is a double strand
prevents actin–myosin interaction
4. Troponin:
- a globular protein
binds tropomyosin to G actin
controlled by Ca2+
29. Troponin and Tropomyosin
Initiating Contraction
Ca2+ binds to receptor on troponin
molecule
Troponin–tropomyosin complex changes
Exposes active site of F actin
Figure 10–7b
30. A Thick Filament
Contain twisted myosin subunits
Contain titin strands that recoil after stretching
31. The Mysosin Molecule
• Tail:
– binds to other myosin molecules
• Head:
– made of 2 globular protein subunits
– reaches the nearest thin filament
32. Mysosin Action
• During contraction, myosin heads:
– interact with actin filaments, forming
cross-bridges
– pivot, producing motion
33. Skeletal Muscle Contraction
• Sliding filament
theory:
– thin filaments of
sarcomere slide toward
M line
– between thick filaments
– the width of A zone
stays the same
– Z lines move closer
together
Sliding Filaments
34. What are the components
of the neuromuscular
junction, and the events
involved in the neural control
of skeletal muscles?
36. The Process of Contraction
• Neural stimulation of sarcolemma:
– causes excitation–contraction coupling
• Cisternae of SR release Ca2+
:
– which triggers interaction of thick and thin
filaments
– consuming ATP and producing tension
39. The Neuromuscular Junction
• Is the location of neural stimulation
• Action potential (electrical signal):
– travels along nerve axon
– ends at synaptic terminal
Synaptic Terminal
• Releases neurotransmitter
(acetylcholine or ACh)
• Into the synaptic cleft (gap between
synaptic terminal and motor end plate)
40. The Neurotransmitter
• Acetylcholine or ACh:
– travels across the synaptic cleft
– binds to membrane receptors on
sarcolemma (motor end plate)
– causes sodium–ion rush into sarcoplasm
– is quickly broken down by enzyme
(acetylcholinesterase or AChE)
41. Action Potential
• Generated by increase in sodium ions
in sarcolemma
• Travels along the T tubules
• Leads to excitation–contraction
coupling
42. Excitation–Contraction Coupling
• Action potential reaches a triad:
– releasing Ca2+
– triggering contraction
• Requires myosin heads to be in
“cocked” position:
– loaded by ATP energy
43. key steps involved in contraction
of a skeletal muscle fiber
Exposing the Active Site
Figure 10–11
48. 5 Steps of the Contraction Cycle
1. Exposure of active sites
2. Formation of cross-bridges
3. Pivoting of myosin heads
4. Detachment of cross-bridges
5. Reactivation of myosin
52. Rigor Mortis
• A fixed muscular contraction after
death
• Caused when:
– ion pumps cease to function
– calcium builds up in the sarcoplasm
53. A Review of Muscle Contraction
Table 10–1 (1 of 2)
54. A Review of Muscle Contraction
Table 10–1 (2 of 2)
55. KEY CONCEPT
• Skeletal muscle fibers shorten as thin
filaments slide between thick filaments
• Free Ca2+
in the sarcoplasm triggers
contraction
• SR releases Ca2+
when a motor neuron
stimulates the muscle fiber
• Contraction is an active process
• Relaxation and return to resting length is
passive
56. What is the mechanism
responsible for tension
production in a muscle fiber,
and what factors determine
the peak tension developed
during a contraction?
57. Tension Production
• The all–or–none principal:
– as a whole, a muscle fiber is either
contracted or relaxed
Tension of a Single Muscle Fiber
• Depends on:
– the number of pivoting cross-bridges
– the fiber’s resting length at the time of
stimulation
– the frequency of stimulation
59. Length–Tension Relationship
• Number of pivoting cross-bridges depends
on:
– amount of overlap between thick and thin fibers
• Optimum overlap produces greatest amount
of tension:
– too much or too little reduces efficiency
• Normal resting sarcomere length:
– is 75% to 130% of optimal length
60. Frequency of Stimulation
• A single neural stimulation produces:
– a single contraction or twitch
– which lasts about 7–100 msec
• Sustained muscular contractions:
– require many repeated stimuli
65. Treppe
• Repeated stimulations immediately
after relaxation phase:
– stimulus frequency < 50/second
• Causes a series of contractions with
increasing tension
67. Wave Summation
• Repeated stimulations before the end
of relaxation phase:
– stimulus frequency > 50/second
• Causes increasing tension or
summation of twitches
68. • If rapid stimulation
continues and muscle
is not allowed to
relax, twitches reach
maximum level of
tension
Incomplete Tetanus
Twitches reach maximum tension
69. Complete Tetanus
• If stimulation
frequency is high
enough, muscle
never begins to
relax, and is in
continuous
contraction
70. What factors affect peak
tension production during the
contraction of an entire
skeletal muscle, and what is
the significance of the motor
unit in this process?
71. InterActive Physiology:
Contraction of Whole Muscle
PLAY
Tension Produced by
Whole Skeletal Muscles
• Depends on:
– internal tension produced by muscle fibers
– external tension exerted by muscle fibers
on elastic extracellular fibers
– total number of muscle fibers stimulated
73. Motor Units in a Skeletal Muscle
• Contain hundreds of muscle fibers
• That contract at the same time
• Controlled by a single motor neuron
InterActive Physiology:
Contraction of Motor Units
PLAY
74. Recruitment (Multiple
Motor Unit Summation)
• In a whole muscle or group of muscles,
smooth motion and increasing tension
is produced by slowly increasing size or
number of motor units stimulated
75. Maximum Tension
• Achieved when all motor units reach
tetanus
• Can be sustained only a very short time
• Sustained Tension
• Less than maximum tension
• Allows motor units to rest in rotation
76. KEY CONCEPT
• Voluntary muscle contractions involve
sustained, tetanic contractions of
skeletal muscle fibers
• Force is increased by increasing the
number of stimulated motor units
(recruitment)
77. Muscle Tone
• The normal tension and firmness of a
muscle at rest
• Muscle units actively maintain body
position, without motion
• Increasing muscle tone increases
metabolic energy used, even at rest
78. What are the types of
muscle contractions,
and how do they differ?
•
•
2 Types of Skeletal
Muscle Tension
Isotonic contraction
Isometric contraction
84. Resistance and Speed
of Contraction
• Are inversely related
• The heavier the resistance on a
muscle:
– the longer it takes for shortening to begin
– and the less the muscle will shorten
85. Muscle Relaxation
• After contraction, a muscle fiber
returns to resting length by:
– elastic forces
– opposing muscle contractions
– gravity
86. Elastic Forces
• The pull of elastic elements (tendons
and ligaments)
• Expands the sarcomeres to resting
length
87. Opposing Muscle Contractions
• Reverse the direction of the original
motion
• Are the work of opposing skeletal muscle
pairs
Gravity
• Can take the place of opposing muscle
contraction to return a muscle to its
resting state
88. What are the mechanisms by
which muscle fibers obtain
energy to power contractions?
89. ATP and Muscle Contraction
• Sustained muscle contraction uses a lot
of ATP energy
• Muscles store enough energy to start
contraction
• Muscle fibers must manufacture more
ATP as needed
90. ATP and CP Reserves
• Adenosine triphosphate (ATP):
– the active energy molecule
• Creatine phosphate (CP):
– the storage molecule for excess ATP
energy in resting muscle
91. Recharging ATP
• Energy recharges ADP to ATP:
– using the enzyme creatine phosphokinase
(CPK)
• When CP is used up, other mechanisms
generate ATP
93. ATP Generation
• Cells produce ATP in 2 ways:
– aerobic metabolism of fatty acids in the
mitochondria
– anaerobic glycolysis in the cytoplasm
94. Aerobic Metabolism
• Is the primary energy source of resting
muscles
• Breaks down fatty acids
• Produces 34 ATP molecules per glucose
molecule
95. Anaerobic Glycolysis
• Is the primary energy source for peak
muscular activity
• Produces 2 ATP molecules per
molecule of glucose
• Breaks down glucose from glycogen
stored in skeletal muscles
96. Energy Use and Muscle Activity
• At peak exertion:
– muscles lack oxygen to support
mitochondria
– muscles rely on glycolysis for ATP
– pyruvic acid builds up, is converted to
lactic acid
99. What factors contribute to
muscle fatigue, and what are
the stages and mechanisms
involved in muscle recovery?
100. Muscle Fatigue
• When muscles can no longer perform a
required activity, they are fatigued
Results of Muscle Fatigue
1. Depletion of metabolic reserves
2. Damage to sarcolemma and sarcoplasmic
reticulum
3. Low pH (lactic acid)
4. Muscle exhaustion and pain
101. The Recovery Period
• The time required after exertion for
muscles to return to normal
• Oxygen becomes available
• Mitochondrial activity resumes
102. The Cori Cycle
• The removal and recycling of lactic acid by
the liver
• Liver converts lactic acid to pyruvic acid
• Glucose is released to recharge muscle
glycogen reserves
Oxygen Debt
• After exercise:
– the body needs more oxygen than usual to
normalize metabolic activities
– resulting in heavy breathing
103. KEY CONCEPT
• Skeletal muscles at rest metabolize
fatty acids and store glycogen
• During light activity, muscles generate
ATP through anaerobic breakdown of
carbohydrates, lipids or amino acids
• At peak activity, energy is provided by
anaerobic reactions that generate
lactic acid as a byproduct
104. Heat Production and Loss
• Active muscles produce heat
• Up to 70% of muscle energy can be lost as
heat, raising body temperature
Hormones and Muscle Metabolism
• Growth hormone
• Testosterone
• Thyroid hormones
• Epinephrine
105. How do the types of
muscle fibers relate to
muscle performance?
106. Muscle Performance
• Power:
– the maximum amount of tension produced
• Endurance:
– the amount of time an activity can be
sustained
• Power and endurance depend on:
– the types of muscle fibers
– physical conditioning
107. 3 Types of Skeletal Muscle Fibers
1. Fast fibers- Contract very quickly
• Have large diameter, large glycogen reserves, few
mitochondria
• Have strong contractions, fatigue quickly
2. Slow fibers-Are slow to contract, slow to fatigue
•
•
•
Have small diameter, more mitochondria
Have high oxygen supply
Contain myoglobin (red pigment, binds oxygen)
3. Intermediate fibers-Are mid-sized
•
•
Have low myoglobin
Have more capillaries than fast fiber, slower to
fatigue
110. Muscles and Fiber Types
• White muscle:
– mostly fast fibers
– pale (e.g., chicken breast)
• Red muscle:
– mostly slow fibers
– dark (e.g., chicken legs)
• Most human muscles:
– mixed fibers
– pink
111. Muscle Hypertrophy
• Muscle growth from heavy training:
– increases diameter of muscle fibers
– increases number of myofibrils
– increases mitochondria, glycogen reserves
Muscle Atrophy
• Lack of muscle activity:
– reduces muscle size, tone, and power
112. What is the difference
between aerobic and
anaerobic endurance, and
their effects on muscular
performance?
Physical Conditioning –
Improves both power and
endurance
113. Anaerobic Endurance
• Anaerobic activities (e.g., 50-meter
dash, weightlifting):
– use fast fibers
– fatigue quickly with strenuous activity
• Improved by:
– frequent, brief, intensive workouts
– hypertrophy
114. Aerobic Endurance
• Aerobic activities (prolonged activity):
– supported by mitochondria
– require oxygen and nutrients
• Improved by:
– repetitive training (neural responses)
– cardiovascular training
115. KEY CONCEPT
• What you don’t use, you loose
• Muscle tone indicates base activity in motor
units of skeletal muscles
• Muscles become flaccid when inactive for
days or weeks
• Muscle fibers break down proteins, become
smaller and weaker
• With prolonged inactivity, fibrous tissue may
replace muscle fibers
116. What are the structural and
functional differences between
skeletal muscle fibers and
cardiac muscle cells?
117. Structure of Cardiac Tissue
• Cardiac muscle is
striated, found only in
the heart
Figure 10–22
118. 7 Characteristics of Cardiocytes
• Unlike skeletal muscle, cardiac muscle
cells (cardiocytes):
– are small
– have a single nucleus
– have short, wide T tubules
119. 7 Characteristics of Cardiocytes
– have no triads
– have SR with no terminal cisternae
– are aerobic (high in myoglobin,
mitochondria)
– have intercalated discs
120. Intercalated Discs
• Are specialized contact points between
cardiocytes
• Join cell membranes of adjacent
cardiocytes (gap junctions, desmosomes)
Functions of Intercalated Discs
• Maintain structure
• Enhance molecular and electrical
connections
• Conduct action potentials
121. Coordination of Cardiocytes
• Because intercalated discs link heart
cells mechanically, chemically, and
electrically, the heart functions like a
single, fused mass of cells
122. 4 Functions of Cardiac Tissue
1. Automaticity:
–
–
contraction without neural stimulation
controlled by pacemaker cells
2. Variable contraction tension:
– controlled by nervous system
3. Extended contraction time
4. Prevention of wave summation and tetanic
contractions by cell membranes
123. Role of Smooth Muscle in Body
Systems
• Forms around other tissues
• In blood vessels:
– regulates blood pressure and flow
• In reproductive and glandular systems:
– produces movements
• In digestive and urinary systems:
– forms sphincters
– produces contractions
• In integumentary system:
– arrector pili muscles cause goose bumps
124. What are the structural and
functional differences between
skeletal muscle fibers and
smooth muscle cells?
126. Comparing Smooth
and Striated Muscle
• Different internal organization of actin
and myosin
• Different functional characteristics
127. 8 Characteristics of
Smooth Muscle Cells
1. Long, slender, and spindle shaped
2. Have a single, central nucleus
3. Have no T tubules, myofibrils, or
sarcomeres
4. Have no tendons or aponeuroses
128. 8 Characteristics of
Smooth Muscle Cells
5. Have scattered myosin fibers
6. Myosin fibers have more heads per
thick filament
7. Have thin filaments attached to
dense bodies
8. Dense bodies transmit contractions
from cell to cell
129. Functional Characteristics
of Smooth Muscle
1. Excitation–contraction coupling
2. Length–tension relationships
3. Control of contractions
4. Smooth muscle tone
130. Excitation–Contraction Coupling
• Free Ca2+
in cytoplasm triggers
contraction
• Ca2+
binds with calmodulin:
– in the sarcoplasm
– activates myosin light chain kinase
• Enzyme breaks down ATP, initiates
contraction
131. Length–Tension Relationships
• Thick and thin filaments are scattered
• Resting length not related to tension
development
• Functions over a wide range of lengths
(plasticity)
132. Control of Contractions
• Subdivisions:
– multiunit smooth muscle cells:
• connected to motor neurons
– visceral smooth muscle cells:
• not connected to motor neurons
• rhythmic cycles of activity controlled by
pacesetter cells
133. Smooth Muscle Tone
• Maintains normal levels of activity
• Modified by neural, hormonal, or
chemical factors
135. SUMMARY (1 of 3)
• 3 types of muscle tissue:
– skeletal
– cardiac
– smooth
• Functions of skeletal muscles
• Structure of skeletal muscle cells:
– endomysium
– perimysium
– epimysium
• Functional anatomy of skeletal muscle fiber:
– actin and myosin
136. SUMMARY (2 of 3)
• Nervous control of skeletal muscle fibers:
– neuromuscular junctions
– action potentials
• Tension production in skeletal muscle fibers:
– twitch, treppe, tetanus
• Tension production by skeletal muscles:
– motor units and contractions
• Skeletal muscle activity and energy:
– ATP and CP
– aerobic and anaerobic energy
137. SUMMARY (3 of 3)
• Skeletal muscle fatigue and recovery
• 3 types of skeletal muscle fibers:
– fast, slow, and intermediate
• Skeletal muscle performance:
– white and red muscles
– physical conditioning
• Structures and functions of:
– cardiac muscle tissue
– smooth muscle tissue